Thiirane or episulfide resins prepared from the corresponding glycidyl ether based resins have been found to possess higher reactivity (shorter gel time) to aliphatic and cycloaliphatic amine curing agents as well as polyamidoamines. Reactivity to aromatic amine curing agents has been found to be reduced. Additionally, the curing of the thiirane resin proceeds at a lower temperature that that of the corresponding epoxy resin. Incremental enhancement of some mechanical properties of cured thiirane resins or blends of thiirane and epoxy resins occurs over those of the epoxy resin, per se.
The polythiirane resin compositions of the present invention contain one or more rodlike mesogenic moieties. The polythiirane resins exhibit ordering of the molecular chains in one or more of the melt phase, advanced compositions thereof, cured compositions thereof or the homopolymers (self-cured) thereof. This morphology is susceptible to flow induced orientation during processing which can result in enhanced unidirectional mechanical properties. The rodlike mesogenic structures incorporated into the polythiirane provide an improvement in one or more of its properties. The property improvements obtained with polythiirane resins of this type can be unidrectionally enhanced by electric or magnetic fields or by drawing and/or shear forces applied during processing and/or curing. In addition to property improvements, it would be desirable to have available resins which are capable of self-curing into the liquid crystal state thus eliminating the need of a curing agent. The polythiiranes of the present invention are capable of self-curing into the liquid crystal state. However, in some or many instances, it may be desirable to employ a curing agent for the polythiiranes of the present invention.